1. Field of the Invention
The present invention relates to image data processing method and image processing apparatus for making appropriate corrections to an image blurred due to camera shake, especially for an image with a moving subject, through computer processing of a captured image.
2. Description of the Related Art
There exist blur-compensation technologies developed to prevent blurring of an image due to camera shake. There are various types of blur-compensation technologies including optical correction type and image synthesizing type. Of these technologies, image synthesizing type of blur-compensation is suited for devices, etc. that are required to be compact since the technology does not require a corrective lens or a drive mechanism for its optical device.
In Japanese Unexamined Patent Application Publication Nos. 2003-78807 and 1997-261526, technologies are proposed to compensate for blurring by calculating the motion vector between multiple still images captured by an imaging device such as a camera.
With an image synthesizing type, motion vectors between multiple images are calculated first, and a relative displacement between images is obtained from the motion vectors. Then, a synthesized image is obtained from an addition process utilizing applicable pixel values in the multiple images with their displacement corrected.
However, if there is a moving subject in a captured image, the location of the subject will change between images, and existing image synthesizing type correction creates a synthesized image with a blurry ghost-like subject in the image.
FIG. 8 is an example of a captured image using existing image synthesizing type of blur-compensation. Image (a) through image (d) are consecutively captured input images. It is noticeable that the motorbike, the image's subject, is moving diagonally towards the top right corner of the image.
Image (h) is the corrected and synthesized image created using image (a) through image (d). Among photography subjects in the image (h), the motorbike that is a moving subject that appears like an after-image.
The present invention was made in view of the above issue. The object of this invention is to provide an image data processing method and image processing apparatus where a more accurate blur-compensated image can be obtained by preventing the photographic subject from becoming indistinct even if there is a moving subject in a captured image.